package com.stephen.data.stack;

import java.util.Scanner;

/**
 * @author: stephen
 * @create: 2020-01-30 22:05
 * @description: 用数组模拟栈
 */
public class ArrayStackDemo {

    public static void main(String[] args) {
        ArrayStack stack = new ArrayStack(5);
        String key = "";
        boolean loop = true;
        Scanner scanner = new Scanner(System.in);
        while (loop) {
            System.out.println("show: 表示遍历");
            System.out.println("exit: 表示退出");
            System.out.println("push: 表示压栈");
            System.out.println("pop: 表示出栈");
            System.out.println("请输入[show],[exit],[push],[pop]");
            key = scanner.next();
            switch (key) {
                case "show":
                    stack.list();
                    break;
                case "push":
                    System.out.println("请输入一个数");
                    int value = scanner.nextInt();
                    stack.push(value);
                    break;
                case "pop":
                    try {
                        int pop = stack.pop();
                        System.out.printf("出栈的数据为[%d] \n",pop);
                    } catch (Exception e) {
                        System.out.println(e.getMessage());
                    }
                    break;
                case "exit":
                    scanner.close();
                    loop = false;
                    break;
                default:
                    break;
            }
        }
        System.out.println("程序退出");
    }
}


class ArrayStack {
    private int maxSize; // 最大容量
    private int[] stack; // 栈
    private int top = -1; // 栈顶,初始值为-1

    public ArrayStack(int maxSize) {
        this.maxSize = maxSize;
        // 初始化数组
        stack = new int[this.maxSize];
    }

    public boolean isFull() {
        return top == maxSize - 1;
    }

    public boolean isEmpty() {
        return top == -1;
    }

    public void list() {
        if (isEmpty()) {
            System.out.println("栈空,无数据~~~");
            return;
        }
        for (int i = top; i >= 0; i--) {
            System.out.printf("stack[%d]为[%d] \n",i,stack[i]);
        }
    }

    // 压栈
    public void push(int value) {
        if (isFull()) {
            System.out.println("栈满,压栈失败~~~");
            return;
        }
        top++;
        stack[top] = value;
    }

    // 出栈
    public int pop() {
        if (isEmpty()) {
            throw new RuntimeException("栈空,没有数据~~~");
        }
        int value = stack[top];
        top--;
        return value;
    }
}